1. Field of the Invention
The present invention relates to an image communication apparatus, a control method therefor, and a storage medium.
2. Description of the Related Art
In recent years, replacement of a conventional circuit-switched telephone network with a network based upon IP (Internet Protocol) techniques has led to widespread dissemination of techniques to provide services via a LAN or an NGN (Next-Generation Network). Here, the NGN denotes an IP network that itself has a bandwidth guarantee function and a security function and realizes a telephone service, a video communication service, a data communication service, and the like in an integrative manner.
A virtual session is established between communication apparatuses in such a LAN or an NGN, and there has been a widespread use of a SIP (Session Initiation Protocol) that guarantees services during a valid session. Various forms of services have been proposed to perform speech communication or image communication, or to perform them simultaneously, using protocols such as the IP and VoIP (Voice Over IP) on a communication apparatus that has established a session using this SIP (Japanese Patent Laid-Open No. 2005-86724). Examples of this image communication include facsimile communication according to a digital facsimile procedure compliant with the ITU-T recommendation T.38, and facsimile communication according to a digital facsimile procedure compliant with the ITU-T recommendation T.30 (T.30 facsimile communication based on deemed voice of VoIP).
However, the foregoing conventional technique has the following problems. In order to perform speech communication and image communication with various communication apparatuses in a LAN or an NGN, it is necessary to comply with a plurality of protocols, and further to perform communication control in accordance with a communication capability of the other party. For example, in the case of image communication during speech communication, in the case where the other party has a single session, and in the case of VoIP, speech communication and the image communication cannot be performed simultaneously, and other restrictions may apply. However, ordinarily, a user does not particularly pay attention to such protocol differences and a communication capability of the other party. Therefore, even if an attempt is made to perform image communication with continuation of speech communication, it may not be possible to continue speech communication depending on used protocols and functions of a communication apparatus of the other party. Moreover, the user cannot know of such things ahead of time, which disadvantageously contributes to user-unfriendliness of communication functions.